Measuring apparatus.



G. H. GIBSON.

MEASURING APPARATUS.

APPLICATION men SEPT.26. 1913.

1,162,475. Patentpd Nov. 30, 1915.

C H H3 111' a INVENTOR %\Ii//TN ESSEs BY Q ATTORNEY UNITED STATES rA nNTorricn.

enonen H. GIBSON, ormon'rcnam, NEW JERSEY.-

mnnsunme arrAnA'rUs.

means;

Specification of Letters Patent. Patented Nqiv, 30,1915.

Application filed September 26, 1913. Serial No. 791,923.

My present invention relates to measur-- ing apparatus, and has for itsobject to provide simple and efiective apparatus for measuring the ratiobetween two separately variable non-electrical forces or quantities.

In the preferred mode of carrying out my invention, I provide simple andeffective means for balancingeach of the two variablenon-electricalforces to be compared, by electromagnetic means, comprising anelectro-magnetic balancing device proper for each of said forces andmeans for supplying an energizing current to each device automaticallyvaried in intensity as required to maintain the balance. The strength ofeach of the two balancing electric currents flowing, one through eachelectro-magnetic balancing device, is thus a measure of thecorresponding non-electrical force balanced, and I obtain the desiredmeasure of the ratio between the two nonelectrical forces orouantitiesto be compared by measuring the difi'erential of the two electricalcurrents by the aid of a suitable instrument.

A measure of the electric current differential may be had by means of asimple, reliable and relatively inexpensive'instrument,

and a further advantage of, my invention. lies in, the fact that I mayseparately indi- 'cate, integrate or record the variations of each ofthe non-electrical forces or quantities compared, by means of -.an'ordinary commercial form of indicating, recording or integratingammeter, through which the corresponding electric current producing thebalancing force is passed.

My invention is of especial utility in and was especially devisedfor-obtaining a ratio to of the quantities of fluid flowing through twoconduits. For this purpose I prefer to employ an electro-magneticbalancing device in which the balancing force exerted is proportional tothe square of the energizing current, to balance each pressuredifferential 'or velocity head forming a measure of the rate of flow ofa fluid through'the corre sponding conduit. With such an arrangement therate of fluid flow through each conduit is itself proportional to thesquare root of the pressure differential balanced by the correspondingelectro magnetic device.

Hence the fluid fiowthrough each conduit.

is in linear proportion to the strength of the electrical currentpassing through the cor responding electro-magnetic balancing device.This simplifies the operation of comparing the two flows and does awaywith any necessity for cam or other rectifying provisions generallyrequired with fiow measuring apparatus of this general character inorder to obtain proportional indications of the individual rates offluid flow, or to directly integrate, or to obtain a record thereofwhich may be readily integrated.

The various features of novelty character- ;izing my invention arepointed out with particularity in the claim annexed to and forming apart of this specification. For a better understanding of the invention.however, and of the advantages possessed byit, reference should be hadto the accompanying-drawings and descriptive matter in which I haveillustrated and described one form in which my invention may be.

embodied.

. Of'the drawings: Figure 1 is a diagrammatic representation. ofapparatus for sep conduit to the flow through the other con- 1 duit; andFig; 2 is a section taken on the line. 2- 2 cf Fig. 1.

,In the apparatus diagrammatically illus-' trated in Fig. 1, ACrepresents the Venturi tube section of a conduit through which one ofthe gases or liquids to be measured and compared flows, and ADrepresents the Venturi tube section through which the other As shown,

fluid flows; for instance, the conduit AC may be the steam pipe leadingaway from a steam generating boiler, and Al) the conduit through whichair or liquid fuel is supplied to the boiler furnace.

Associated with the two Venturi tube sections are two sets ofinstrumentalities. As

these are duplicates, a description of the set diaphragm C, and makestufling box provi sions for the stem B unnecessary.

The stem B is pivotally connected at its upper end to a lever D, to theopposite end of which is secured the movable coil e of theelectro-magnetic balancing device E. the lever D is formed by two metalbars D and D insulated from each other; and formin the terminals of thecoil e. The lever T) is suspended from a fixed support (23 by flexibleconductors d and d connected at their lower ends to the bars D and Drespectively. The knifeedge ivot D carried by the lever D and the stem 3engaging the pivot D are insulated from the bars D and D Theelectromagnetic balancing device E also comprises stationary coils e ande coaxial With and located one above and the other below the coil 6.When an electric current is caused to flow in series through the coilse, e and e by the circuit connections hereinafter referred to the coil 6is attracted by the coil and repelled bythe coil e.

The means employed for adjusting the electric current flow through thecoils e, e and e to impress the required variable balancing force on thelever D, comprises a rheostat G, a reversible electric motor H,

and controlling provisions for operating the latter in one direction orthe other in response to the movements of the lever D out of a neutralposition. The rheostat G, as somewhat conventionally illustrated,comprises a contact member G movable along and engaging one or anotherof the stationary contacts Gr connected at intervals to a. resistanceconductor G As shown, the member G has a threaded passage receiving thethreaded shaft H of the motor H. The motor H in the arrangementillustrated, runs in one direction whena suitable source of electriccurrent is connected to its termin'als H. and H, and in the oppositedirecrepresent pipe contion when current is supplied to the motorterminals H and H.

K represents an electric battery or other suitable source of electriccurrent for the balancing device E and for the motor H. The electriccurrent flowing through the coils of the device E is measured by anammeter I, which may be of any suitable or usual form, adapted toindicate, make a record of, or integrate the flow of currenttherethrough, or perform any two, or preferably perform all three ofthese functions.

represents a rheostat connected in shunt to the ammeter I by which theconstant of the latter may be adjusted.

One terminal of the battery K is connected by the conductor 1 to theflexible support d for the lever D and thereby to the bar D forming oneterminal of the floating coil 6. The bar D forming the other terminal ofthe coil 6 is connected through the flexible conductor 03 and theconductor 2 to one terminal of the stationary coil 6. The

other terminal of the stationary coil 6 is nected by a conductor 3 toone terminal of the coil e 1 The other terminal of the coil e is'connected by a conductor 4 to one terminal of the ammeter I. The secondterminal of the ammeter I is connected by the flexible conductor 5 tothe movable element G of the rheostat-G. The resistance conductor G ofthe rheostat G is connected at one end to the second terminal of thesource of current K by the conductor 6. Connected in series with theconductor 6 is the coil P of the flow comparing instrument Pproper. Thecoil P of the instrument P is connected inseries with the conductor 6pertaining to the conduit AD. The common terminal H of the motor H isconnected by the conductor 7 to the opposite side of the source ofcurrent K from that which is connected to the bar D of lever D. Theother two terminalsH and H of the motor H are connected by conductors 8and 9 to stationary contacts L and LA, respectively, mounted above andbelow the lever D and engaged by the bar D of the latter on a slightmovement of the lever up or down from a neutral position.

When the downward pull of the device E on the lever D is insufficient tobalance the pull on the other end of the lever exerted by thedifferential pressure device B, the lever 11 moves from its normalneutral position into contact with the stationary contact L, and thuscloses the current supply circuit for the motor H comprising the sourceof current K, conductor 1, bar D of lever D, contact L, conductor 8,terminals H and H and conductor 7, leading back to the source of currentK. This causes the motor H to rotate in the direction to move themovable element G of the rheostat G to the left, as

consequent movement of the lever D out of its neutralposition intoengagement with the stationary contact LA will close the energizingcircuit of the motor H including the source ofcurrent K, conductor 1,bar D of lever D, contact LA, conductor 9, motor terminals .H and H andconductor 8.

This causes the motor H to rotate in the direction to move the element Gof the rheo stat G to the right and thereby increase the resistance incircuit with, and reduce the current flowing through the coils e, e" and6 until the lever D is returned to its 'normal neutral position;

Inasmuch as the difierential of the pressures exerted on the stem B ofeach diiferential pressure device B, through its diaphragms vG, C and Cis proportional to the square of the fluid rate of flow through thecorresponding Venturi tube section, while the balancing force exerted bythe corresponding electro-magnetic balancing device E is proportional tothe square of the electric current flowing throughthe coils "of thelatter, the intensity of the electric current passing through thecorresponding conductor 6 and indicated, integrated and recorded by theammeter I will be in linear proportion to the rate of fluid flow throughthe conduit of which the corresponding Venturi tube section forms apart.

The electrical instrument P employed to obtain a direct measure of theratio between the volumes of flow through the conduits AG and ADcomprises'in addition to the two coils P and P arranged at right anglesto one another, an armature P mounted on a spindle P which isdiametrally disposed 1 with reference to each of the coils P and P andcarries an. indicating arm P sweeping over a quadrant scale P Thecurrents passing through the coils Pv and P and the magnetic forcesexerted by these coils will be proportional to the volumes of flowthrough the conduits AC and AD, respectively. The torque exerted by eachcoil on the armature P tending to set the latter at right anglesto theplane of the coil will be proportional to the product of the magneticforce of the coil multiplied by the cosine of the angle of inclinationof the armature to the plane of the coil. Inasmuch as the an mature 1will occupy the position at any instant at which-the torque exerted onit by one coil balances the torque exerted by the other coil, itfollows, therefore, that if a equals the rate of flow through theconduit AC, and 6 equals the rate of flow through the conduit ADyand 0equals the angle of inclination of the armature P to the coil P,

for instance; then a cosine 0=b cosine (906) g cosine 90 -0 b cosine 6Since cosine (90 6) =sine of 6, the ratio of the two rates of flow i.e., will thus be equal to the tangent of the angle 0.

It will be apparent of course that with Y the apparatus described theindications ob-' tained do not depend upon the constancy of the-voltageof the source of current K and are unafiected by changes in theconstants, so to speak, of the rheostats G and J, such as might resultfrom dirty contacts, and that the only parts of the electrical'apparatuswhich need to be carefully constructed and adjusted are theelectro-magnetic balancing devices E, ammeters I and the instrument P.

Each device E and lever D are essentially'the same in construction andmode of operationas parts. of the well known Kelvin current balance, andthe construction and adjustment of this portion of the apparatus to givethe desired reliability and accuracy is a relatively simple matter. i

The instrument P is simple in form, and may readily be made reliable andhighly accurate in operation. Each ammeter I may obviously be any one ofnumerous highly satisfactory and efficient types in cornmercial use atthe present time.

A characteristic advantage of the apparatus described arises from thefact-that the only movements of the diaphragms C, C and C and of thecoils e relative to the coils e and e required are those necessary toaccommodate the limited movement of the lever D between the contacts Land LA. In practice these movements may be so small that they do notappreciably affect the inductive relation of either coil 6 with thecorresponding coils e and 6 or the flexibility of the diaphragms.

While in accordance'with the provisions of the statutes I haveillustrated and described the best form of my invention now known to me,it will be apparent to those skilled in the art that changes may be madein the form of apparatus disclosed without departing from the spirit ofmy invention,

and-that in some cases certain features of my invention mayadvantageously be used without a corresponding use of other features.

Having now' described my invention, what -sive to the velocity head atsome point in 10 I claim as new and desire to secure by Leteach conduitfor causing an electric current ters Patent, is: proportional to theflow through said confl Apparatus1 for comgaring the rates of duit topass through a corresponding coil.

ow t roug two con uits com risin an 1 instrument consisting of two nn-pai allel v GEORGE GIBSON' coils havin intersecting axes, and apivoted Witnesses: armature e ement magnetically actuated by PAUL C.BAUCEL, each coil and means automatically respon- STANLEY D. BROWN.

